Canal tow paths were never built for speed. They were designed for horses to trudge along, lugging barges and their non-urgent loads. More recently they have become the favourite haunt of people enjoying gentle pursuits such as walking, fishing and boating.

But they have now become the favourite route of new users who are in much more of a hurry - cyclists.

British Waterways reports a notable increase in bike journeys on towpaths, partly because of improvement works, through a lottery-funded project, to create a nationwide network of cycle lanes.

But traditional canal users are not happy. They complain that towpaths have become "cycle superhighways". They are being pushed off these narrow paths, they say, by the sheer volume of cyclists in a tearing hurry to get to and from work.

In short, towpaths have become the new front line in the battle between pedestrians and cyclists. And, at the moment, it is the cyclists who are winning.

One of the main flash points is the narrow and winding Regent's canal that wiggles across north London and cycling-keen boroughs such as Hackney, Islington, and Camden.

"Regents canal could not have been designed better for accidents, there are loads of bends and low bridges," says Neil Edwards, chief executive of the Inland Waterways Association, a charity representing canal users.

"There's only a finite space on the towing path and they are already at capacity especially in central London where the canals are particular narrow and winding and the density of population is particularly great."

Since the suicide bombings on London's transport network in July last year, there has been a marked increase in cycling everywhere in the capital, but notably on the canals. At one stretch earlier this summer, British Waterways counted 300 commuting cyclists, or one every 25 seconds. This increase in use has caused tempers to fray.

Ed Fox, communications manager of British Waterways London says: "The most noticeable change for us has been an increase in the number of complaints."

In July one correspondent wrote: "For the past year I have taken this route to and from work and have noticed that cyclists are growing in frequency."

She complains: "They tut with annoyance if you do not get out of their way. My partner and I have been forced to walk in single file along this route which is supposed to be a leisurely walk."

The unnamed pedestrian fears serious accidents on the tow paths.

"I have been knocked on my arm and my hand by passing cyclist and have also been cycled into under a bridge. I am sure it is only a matter of time before there is a more major accident."

She adds: "There is quite a lot of tension down this towpath as pedestrians fear for their safety, and cyclists are commuting fast and want to get home without obstacles in their way."

But for cyclists the canal network is a safe haven from the dangers of the roads. They would rather share a route with an ambling pedestrian than a speeding car.

"The canal tow paths are a godsend," says Richard George, off-road campaigner for the Cycling Touring Club. "The canal is a beautiful place to relax and get away from the hustle and bustle of the roads network."

Sustrans, the charity behind the lottery funded National Cycle Network, is also keen to encourage bikes on the tow path. More than 500 miles of its 10,000 mile network runs alongside canals and rivers.

"Because they are flat, tow paths make excellent cycle paths," a spokeswoman said.

But pedestrians feel that just as cyclists have been driven off the roads they are now being driven - or cycled - off the towpaths.

"The tow paths are being hijacked and given over to cycling superhighways. They should be for everyone," says Howard Piper, an Islington resident who likes to walk and jog on the Regent's Canal.

He says: "Cycling on the tow path is no safer than cycling on a pavement.

"It has grown to a point where the cyclist dominate to the detriment of other users. It's very dangerous."

Piper partly blames Transport for London for printing cycle maps of the capital that highlight the canals as cycle routes. He argues that for safety reasons, cycling should be banned on some stretches rather than encouraged.

George describes this as a "horrendous" prospect. He claims the threat posed by cyclists is one of "perception not reality".

But he has a warning for fellow cyclists. "We need to be considerate of other canal users, otherwise we'll lose the right to use the tow paths," he says.

And even George accepts that tow paths are not suitable for everyday commuter cycling.

"In some places they are not even wide enough for two cyclists to pass each other. They are more suited to pootling about rather than flying along at 15mph."

For other canal users there is too little pootling and too much commuting.

Edwards says: "We are quite happy to encourage recreational cycling for families ambling along on a Sunday afternoon, but we are against using the canal for commuting. Getting from A to B as fast as possible is dangerous.

British Waterways has become so concerned by the problem that it plans to carry out a safety audit on six stretches of the tow path where cycling is popular.

It is also urging cyclists to be more "sensible".

Mr Fox says: "We want to encourage cycling on the tow path. Where we have a problem is people going too fast. The point that cyclists need to remember is that it is a shared use path."

On some stretches of the 2,000-mile network it has put up signs urging cyclists to give pedestrians the right of way, to dismount under low bridges and to cycle at only 6mph - or twice walking speed.

Mr Fox admits the British Waterways has no power to enforce these rules. "No one is going to stop you with a speed gun," he says, "it is a way of saying 'think about other users of the tow path'."

The signs also say that cyclists need a permit to use the canal. Few cyclists know this, and fewer still own a permit. And as Fox admits, "you are not going to be sent to the colonies for not having one."

He also reveals that BW is reviewing the future of cycle permits. "The people who have a permit are not the problem, they don't mow people down," he says.

Howard Piper is not convinced by attempts to encourage more responsible cycling. "It's naïve to assume that you can control cyclists, there is no one to police them," he says.

But Richard George is more hopeful: "If cyclists complied with British guidelines there wouldn't be a problem."

He adds: "If cyclists felt safer on the roads, they wouldn't need to go onto the tow paths."